Manufacture of pure 1-nitro-2-methylanthraquinone



Patented June 2, 1925.

UNITED STATES PATENTIOFFICE.

HANS nnoann rrnnz, or KILGHBERG, nnnn zunton, SWITZERLAND, AssIeNon *rosoorn'ry CHEMICAL worms vrormERnY- sANnoz, OF -BASEL, SWITZERLAND.

MANUFACTURE OF PURE 1-NITRO-2-METHYLANTHRAQUINONE.

No Drawing.

To all whom it may concern:

Be it known that I, HANS EDUARD Franz, a citizen of the SwissConfederation, and residing at Kilchberg, near Zurich, Switzer- 5 land,have invented new and useful Improvements in the Manufacture of Pure1-Nitro-2-MIethylanthraquinone, of which the following is a full, clear,and exact specification. I

The present invention relates to pure 1-nitro-2-methylanthraquinone.

Crude nitromethylanthraquinon'e contains a considerable numberofisomers. It has been found that the crude product may be easilypurified by heating it for some time with salts of sulfurous acid in anaqueous suspension. The 1-nitro-2-methylanthraquinone is not. changed bythis operation, whilst the isomers, of which probably two have beenascertained .up to now, will go into solution as sulfo acids.l-nitro-2-methylanthraquinone yields at once a chemically pure1-amin0-2-methy1anthraquinone when treated with sodium sulfide. Thebromoand other derivatives ob-. tained therefrom are very pure and melt"in part at a temperature which is 4050' C. 0

higher thanhas been observed hitherto.

The following examples illustrate the invent-ion, the parts being byweight-:

' Example I.

part of 2-methylanthraquinone,gwhich has first been washed neutral, ismade into a paste with some water. Thereto there are added 3 parts ofsodium sulfite dissolved in parts of water. The whole is heated for fivehours in a. reflux apparatus. The

pure 1-nitro 2-methylanthraquinone, sisting in heating for some time thecrude The purifiedv sure.

The crude nitro-product obtained from 1 Application filed August 9,1924. Serial No. 731,212. 1

Example :2.

111 parts of methylanthraquinone are nitrated as usual. The I moistnitration product is introduced into an aqueous solution of 333 parts ofsodium sulfite in about 1800 to 2000 parts of water and heated inanautoclavefor 6 hours to 110-115 C. After cooling the whole is filteredby suction and thoroughly washed with boiling waterf hat I claim is: 1.The "process for the manufacture of nitromethylanthraquinone in anaqueous suspension with salts of sulfurous acid.

2. The process for the manufacture of pure-1nitro-2-methylanthraquinone, consisting in heating for some time thecrude nitromethylanthraquinone in an aqueous suspension with salts ofsulfurous acid under pressure.

3. The process for the manufacture of pure1-nitro-2-methylanthraquinone, consisting in heating for some time thecrude nitromethylanthraquinone in an aqueous suspension with sodiumsulfite under pres- COI1-- In witness whereof I have hereunto signed myname this 23 day of July 1924, in the presence of two subscribingwitnesses.

' HANS EDUARD FIERZ.

\Vitnesses:

WEB Hanson, 'OSSOKAR WorIoKnu.

